50 stickers are in 3 boxes.
The 1st box has 8 times as many stickers as the 2nd box.
The 3rd box is 2 times as many as the 1st box.
How many more stickers are there in the 2nd box and 3rd box than in the 1st box?
Choose the box with the least stickers to be 1 u.

Number of stickers in the 2nd box = 1 u
Number of stickers in the 1st box = 8 x 1 u = 8 u
Number of stickers in the 3rd box = 2 x 8 u = 16 u

Total number of stickers
= 1 u + 8 u + 16 u
= 25 u

25 u = 50
1 u = 50 ÷ 25 = 2

Number of more stickers in the 2nd box and 3rd box than the 1st box
= Total number of stickers in 2nd box and 3rd box - Number of stickers in 1st box
= 1 u + 16 u - 8 u
= 9 u
= 9 x 2
= 18

Answer(s): 18